COASTAL HABITATS WITHIN FLOOD RISK ASSESSMENTS: ROLE OF THE 2D SPR APPROACH

Abstract

Coastal habitats are highly threatened ecosystems that are sensitive to complex sets of natural and human drivers. Europe’s coastal habitats are protected from damage due to human activity by the EU Habitats Directive, and are required to be mapped within flood risk assessments by the EU Floods Directive. Ecological vulnerability and risk assessments are a common way of assessing the impacts on these habitats due to human and natural drivers. Coastal flood risk assessments therefore often include assessments of the vulnerability of coastal habitats. Flood risk assessments also evaluate, where relevant, the mitigation services provided by coastal habitats. The two aspects of coastal habitats – their flood mitigation service and their ecological vulnerability are strongly correlated; however these are usually treated separately within flood risk assessments. One of the goals of the EU THESEUS project is the integrated consideration of coastal habitats within flood risk assessments. This paper investigates the integration within flood risk assessments of the two aspects of coastal habitats using the 2D SPR conceptual model. The construction of the model is first illustrated by application to a generic study site. The model is then applied to a case-study where data on habitat elevations and vulnerabilities to flood events have been collected. The model provides a unique and robust means of combining information on ecological vulnerability indices for different habitat associations with information on their distribution and spatial relationships within the coastal floodplain. Used in conjunction with information on habitat vulnerability indices, the conceptual model serves as a powerful tool for integrated and structured consideration of coastal habitats within flood risk assessments